The purpose of this research was to give an empirical answer to the question of what types of strategies small firms should employ in order to maintain high performance over time. "Small-sized firms" in general refer to the so-called small and medium firms. Due to the availability of appropriate data, however, this study used the smallest class of firms as its sample which are listed on the Tokyo and/or Osaka stock exchanges. Various interesting findings obtained from the two-year research project are summarized as follows.First, the main hypothesis in this study, "To maintain high profitability over the industry life cycle, small firms tend to employ different types of product-line strategies according to different stages of the cycle such as the introduction stage or the declining stage," was not supported at all by the smallest class of listed industrial goods manufacturers. High-performing smallest listed producers of industrial goods, in fact, tend to show sustained high performance both in profitability and in sales growth without significant changes in their product lines over a period of some 20-30 years. Even in matured industries typically represented by the steel industry or the chemical industry, the smallest high-performing listed firms have been growing far above industry growth.Second, the above mentioned fact suggests that these firms have been successful at the cost of their competitors' market share. Results of financial analysis on the high-performing sample firms clearly show that they have been trying to slash excess costs more in growing industries such as electronics or automobile parts than in stagnating industries. It is accordingly suggested that high-performing small listed producers in stagnating industries have employed cost leadership strategies to maintain their numbers both in profitability and in sales growth.